Fuse construction



March 9, 1937 w. o. SCHULTZ 299739183 FUSE CONSTRUCTION Filed Dec. 24, 1954 1 15 21 J5 J5 ibza a JZ 15. 9 J1 19 z Z9 Z5 22, 50 I a 6 INVENTOR.

ATT NEY.

Patented Mar. 9, 1937 rUsE eonsrnuc'rron William 0. Schultz, South Milwaukee, Wis, as-

signor to Line Material Company, South Mil= waukee, Win, a corporation of Delaware Application December 24, 1934, Serial No. 358,903

20 Claims.

This invention relates to a drop-out'fuse construction.

Objects of this invention are to provide a drop-out fuse in which afuse unit, which may include a fuse tube and fuse link, is provided and is pivotally mounted adjacent its lower end by mechanism holding the fuse in place through the medium of the fusible link, so that when the fuse link is severed, the fuse will first drop downwardly disengaging itself from the upper stationary contact and will then rock outwardly away from the upper contact, thus providing maximum spacing after the fuse has blown.

Further objects are to provide a drop-out fuse in which a very simple and effective type of upper contact is employed-which is formed of spring like or resilient material, which has a horn shape to serve the double purpose of guiding the upper contact into place'when the fuse is rocked to closed position, and also has a horn contact which Further objects are to provide a fuse construction in which the upper stationary contact is very simply formed of resilient material with- 5 divergent hornlike portions and with a looped lower portion acting as a stop for limiting the closing motion of the fuse tube at the proper point after the upper contact has passed the shouldered portions of the resilient hornlike members to thereby be yieldingly retained in place, the looped portion providing downward pressure, affording an excellent electrical contact between the upper contact of the fuse tube and the stationary upper contact, and also providing the downward pressure to assist the fuse tube in its initial opening movement. 1

Further objects are to provide a construction which'is very cheap to make,- which is easy to Figure 2 is a fragmentary plan view of the upper contact.

Figure 3 is a fragmentary front view of the upper portion of the construction.

Referring to the drawing, it will be seen that the fuse construction may be carried as a unit by a backing member, such as indicated at i, which may be of channel material or of any other suitable construction. This support l carries the upper insulator 2 and the lower insulator 3. The lower insulator 3 carries an outwardly projecting arm 4 which in turn carries the pintle pin 5 held in place in any suitable manner, as by means of the set screw 6. The lower stationary contact also may carry a connector I of any suitable type.

The upper contact carried by the upper insulatori may be formed of a resilient rod or similar member which has downwardly and outwardly directed slanting arms 8 terminating in downwardly projecting tongues 9. The tongues 9 are clamped in place by means of the outer plate ill, which may carry the connector it, and the inner plate i2, such plates being held together in any suitable manner as by means of bolts l3. This provides, therefore, a very simple and sturdy support for the spaced tongues 9 extending from the arms 8.

The arms 8 continue outwardly and are turned inwardly to provide shouldered portions it, see Figure 2, slightly divergent lips or portions 115, and hornlike widely divergent portions it. The ,hornlike portions it are not only divergent but are curved in a vertical plane, as may be seen from Figure 1, and rearwardly extending portions it project therefrom and are located beneath the portions i5. They have a looped portion it, as is obvious from Figures 1 and 2, which is a rounded loop directly bearing upon the upper contact E9 of the fuse tube 2t and forming a stop for the projecting portion 2! of the upper contact, as may be seen from Figures 1 and 2.

The looped portion bears downwardly on the upper contact and provides a downward thrust for the fuse tube. The shouldered portions i i prevent the fuse tube from rocking outwardly, but due to the resilient nature of the upper contact, the fuse tube may be bodily pulled outwardly slightly spreading the arms of the upper contact. Normally, however, the fuse tube automatically disconnects itself from the upper contact by a downward motion, as will appear as the description proceeds.

The lower portion of the fuse tube is provided with a collar 22 having a projecting arm 23 upon which the ears of a supporting lever 26 are pivoted. This supporting lever 23 has hooklike portions 25 which hook over the pintle pin 5. It also is provided with adownwardly projecting arm 26 carrying a thumb screw-2T which clamps the lower end of the fuse link 28 to the arm 2%, the fuse link, of course, extending from the upper contact'through the open end of the expulsion fuse tube and being clamped to the lever 1d 26, as stated.

Ifdesired, the collar 22 may be provided with a projecting lip 29 which may be received in a suitable socket in the fuse stick for replacing the fuse, it being noted that the fuse can be bodily S15 lifted from the pintle pin by means of the fuse stick, when the fuse is rocked into open position. 'The operation of the apparatus is asfollows:

When the fuse link 28 is ruptured, the arm 26 of the lever 241 is released. The downward pressure 20 of the uppercontact urges the fuse tube downwardly and this is assisted by'the weight of the fuse tube. Consequently, as the pivot point 38 is located in front of the pintle pin 5, the fuse" tube will move downwardly and its lower end-will 25 rock outwardly a slight distance as the fuse tube drops or moves bodily downwardly. This permits the upper contact of the fuse tube to disengage itself from the upper stationary contact and thereafter the fuse tube swings or rocks about tlfe- 30 pintle pin 5 and drops away from the upper contact.

An interval of time occurs before the upper contact of the fuse tube has cleared the upper stationary contact and this interval is normally 85 more than sufficient to allow the expulsion fuse to nevertheless the hornlike upper contact assists in extinguishing any are that might be formed between the upper receding contact of the fuse 45 tube and the hornlike members of the upper stationary contact. This, however, is an abnormal operation and is not 'the normal operation of the device. I After. the fuse has blown, it may be readily o removed by means of a switch stick, as previously described, and may be refused, thus'clamping the arm 26 of the lever 26' against the fuse tube. The fuse tube may then be replaced by means of a switch stick and by means of such switch 55 stick may be rocked'into closed position, the projecting upper portion 2i of; the upper contact of' the fuse tube being guided by-the hornlike members It and sliding'inbetween the restricted portion between the partsl5, see Figure 2, thus 80 slightly springing the'arms apart until the pin 2| of the upper contact'passesbeyond the shouldered portions I l and'is thus locked closed. The looped portion'lfi provides a stop which arrests further inward rocking motion of the fuse tube, ,asis apparent from Figures 1 and2. If desired, the upwardly projecting portion 2| of the upper contact of the fuse unit may be made slightly tapered to facilitate its freeing itwhen the fuse unit drops downwardly.

It willbe seen that the uppefcontact provides a downward pressure which insures positive action of the'device and also is so made that a very simple construction is obtained with a miniself from the lateral pressure of the spring arms ao'iaies mum .of parts and in a highly economical and eifective manner.

It will be seen further that this upper spring like contact cooperates with the peculiar releasing supporting mechanism for the lower end of 5 the fuse tube to insure positive operation of the fuse tube, as the resilient upper contact aids in the initial opening movement of the device.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

, 1. A drop-out fuse comprising a fuse unit pivoted adjacent its lower end and having a projectlng upper contact, a stationary upper contact for said fuse .unit including divergent hornlike spring arms adapted to be rocked apart by the upper contact when the fuse is rocked into closed position, and having a restricted'portion to yield-- ingly restrain the fuse unit from rocking outwardly, said hornlike spring arms having rounded I outer portions, and means for releasing said fuse unit from the hornlike spring arms upon blowing .ingly restrain the fuse unit from rocking. outwardly, said hornlike arms being looped downwardly and rearwardly and forming an inwardly positioned stop for arresting the inward rocking motion of the fuse unit, and means for lowering said fuse unit with respect to the pivotal support adjacent its lower end, said means being released upon blowing of said fuse unit.

for said fuse unit including divergent hornlike spring arms adapted to be rocked apart by the "upper contact when the fuse is rocked into closed position, and having a restricted portion to yieldingly restrain the fuse unit from makingoutwardly, said hornlike arms being loopeddownwardly and rearwardly and forming an inwardly positioned stop for arresting the inward roclnng motion of the fuse unit, and exerting downward pressure on said fuse. unit, and means for loweringsaid fuse unit with respect to the pivotal support adjacent its lower end, said means being released upon blowing of said fuse unit.

4, A drop-outiuse pivoted adjacent; its lower end and having an upper contact, a stationary upper contact for said fuse unitincluding a pair of opposed spring arms for receiving a portion of the upper contact ofv the fuse unit between them and yieldingly laterally gripping such portionand holding the fuse unit against outward rocking motio'msaid spring arms having up wardly curved hornlike portions, and supporting means for holding the fuse unit against downward and outward rocking motion, said supporting means being released upon blowing of the fuseunit. a r

5, A drop-out fuse comprising a fuse unit pivoted adjacent its lower end and having an upper contact provided with-an upper shouldered I portion and an upwardly projecting portion, a stationary upper contact provided with adjacent inwardly urged spring arms for receiving the projecting portion therebetween and having a downwardly urged portion located below said spring arms and bearing upon the shouldered portion of the upper contact of said fuse unit, and supporting means for normally supporting the fuse unit, said supporting means being released upon blowing of said fuse unit and guiding said fuse unit for downward and outward rocking motion.

6. A drop-out fuse comprising a fuse unit having an upper contact, v a stationary upper contact comprising a pair of spring arms having free inner ends, supporting means for clamping said free inner ends, said spring arms being arranged in juxtaposition and adapted to receive the upper contact of the fuse unit between them and having means joining said arms at a point spaced from the supportfor said arms, and supporting means for said fuse unit releasing upon blowing of said fuse unit.

7, A drop-out fuse comprising a fuse unit, supporting means adjacent the lower portion thereof for normally holding said fuse unit in operative position, a fuse link carried by said fuse unit and restraining said supporting means against releasing motion, said fuse unit having an upper contact, and a stationary upper contact, said stationary upper contact being formed of a spring member having free inner ends and having outwardly projecting, substantially vertically loopedhornlike portions and an inwardly looped portion, said inwardly looped portion forming a stop to arrest the inward motion of the fuse 'unit, said spring arms receiving the upper contact of said fuse unit between them. I

8. A drop-out fuse comprising a fuse unit, supporting means adjacent the lower portion thereof for normally holding said fuse unit in operative position, a fuse link carried by said fuse unit and restraining said supporting means against releasing motion, said fuse unit having an upper contact, and a stationary upper contact, said stationary upper contact being formed of a spring member having free inner ends and having outwardly projecting, substantially vertically looped hornlike portions and an inwardly looped portion, said inwardly looped portion forming a stop to arrest the inward motion of the fuse unit, said spring arms receiving the upper contact of said fuse unit between them, said substantially vertically looped hornlike portions being arranged in a divergent manner.

9. A drop-out fuse comprising a fuse unit having an upper contact provided with an upwardly projecting portion, a stationary upper contact for engagement with the upper contact of the fuse unit, said stationary upper contact having opposed spring arms for receiving the projecting portion of the upper contact of the fuse unit between them, said spring arms having a reversely bent portion bearing downwardly on said upper contact, and',a lower supporting means releasing upon blowing of the fuse unit for normally supporting the fuse unit, said supporting means providing downward motion of the fuse unit upon blowing thereof, whereby the upper projecting portion ofthe upper contact may slide v downwardly from engagement with the spring arms.

10. A drop-out fuse comprising a fuse unit having an upper contact provided with an outwardly projecting portion, a stationary upper having opposed spring arms for receiving the projecting portion of the upper contact of the fuse unit between them, said spring arms having a reversely bent portion bearing downwardly on said upper contact, and a lower supporting means releasing upon blowing of the fuse unit for normally supporting the fuse unit, said supporting means providing downward motion of the fuse unit upon blowing thereof, said upper projecting portion of the upper contact of said fuse unit being tapered towards its upper end.

11. A drop-out fuse comprising a fuse unit having an upper contact, a stationary upper contact comprising a pair of spring arms normally receiving a portion of .said upper contact between them, spring means distinct from said spring arms and bearing upon said fuse unit adjacent its upper end and urging said fuse unit longitudinally and tending to slide said upper contact from between said spring arms, and supporting means for said fuse unit releasing upon blowing of said fuse unit.

12. A drop-out fuse comprising a fuse unit having an upper contact provided with a shoulder and a projecting portion, a stationary upper contact comprising a pair of spring arms normally holding the projecting portion of said upper contact between them, means distinct from said spring arms and bearing upon the shouldered portion of said upper contact and tending to slide the projecting portion of said upper contact longitudinally of said fuse unit from between said spring arms, said fuse unit including a fuse link, and supporting means for normally holding said fuse unit in operative position and restrained by said fuse link.

13. A drop-out fuse comprising a fuse unit having an upper contact and a lower contact, a fuse link normally electrically joining said contacts, said upper contact having a shouldered portion and an upwardly projecting portion, a stationary upper contact comprising a pair of spring arms normally holding between them the projecting portion of said upper contact. and having a looped spring portion normally engaging the shouldered portion of said upper contact and tending to slide the projecting portion of said upper contact from between said spring arms, and supporting means adjacent the lower contact normally holding said fuse unit in operative position and restrained against releasing motion by said fuse link.

14. A drop-out fuse comprising a fuse unit pivoted adjacent" its lower end and having a projecting upper contact, a stationary upper contact for said fuse unit including divergent hornlike spring arms adapted to be rocked apart stationary upper contact for said expulsion tubev including divergent hornlike spring arms adapted to be rocked apart by the upper contact, when the expulsion tube is rocked into closed position, and having a restricted portion to yieldlngly restrain the expulsion tube from rocking outwardly, stop means carried bysaid arms spacedfrom said restricted portion and defining a limit of inward rocking motion of the expulsion tube, an expulsible conductor in said tube, and means operable on the occurrence of overload to expel said conductor from said tube and to lower said tube with-respect to the pivotal support adjacent its lower end.

"16. An automatic circuit interrupting structure comprising an arcing tube pivoted adjacent its lower end and having a projecting upper coneluding apair of opposed spring arms for receivpulsion tube between them and yieldingly hold tact, a stationary upper contact for said expulsion tube including. divergent hornlike spring arms adapted to be rocked apart by the upper contact when the'fuse is rocked into closed position, and having a restricted portion to yieldingly restrain the expulsion tube from rocking outwardly, means located below said spring arms and spaced therefrom and urging said tube downwardly, an expulsible conductor in said tube, and current responsive means for releasing said expulsion tube from the hornlike spring arms and for interrupting the circuit within said tube.-

17. An automatic circuit interrupting structure including an expulsion tube pivoted adjacent its lower end and having an upper contact, a stationary upper contact for said expulsion tube ining a portion of the upper contact of the exaoranss pivoted adjacent its lower end and having a projecting upper contact, a stationary upper contact for said fuse unit including divergent hornlike spring arms adapted to be rocked apart by the upper contact when the fuse is rocked into closed position, and having a restricted portion to yieldingly restrain the fuse unit from rocking outwardly, said spring arms having a rearwardly looped portion extending transversely across said spring arms and constituting an inner stop for said fuse unit, and meansffor releasing said fuse unit from the hornlike spring arms upon blowing of said fuse unit,

19. A drop-out fuse comprising a fuse unit piv- ,oted adjacent its lower end and having an upper contact provided withan upper shoulder portion and an upwardly projecting portion, a sta tionary upper contact provided with adjacent inwardly urged spring arms for receiving the projecting portion therebetween and having a downwardly urged portion bearing upon the shouldered portion of the upper contact of said fuse unit, said downwardly urged portion being distinct from said spring arms, and supporting means for normally supporting the fuse unit and movable laterally and upwardly with reference to said fuse unit, said supporting means being released upon blowing of said fuse unit and guiding said fuse unit for downward and outward rocking motion.

20. A drop-out'fuse comprising a fuse unit having an upper contact, a stationary upper contact comprising a pair of spring arms having free inner ends, supporting means for clamping said free inner ends, said spring arms being arranged "in juxtaposition and adapted to eceive the upper contact of the fuse unit bet een them and having means joining said arms at a point spaced from the support for said arms and constituting anJnner stop for said fuse, unit, and supporting means for said fuse unit releasing upon blowing of said fuse unit. 1

v .3 1.4 O; SCHULTZ. 

